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Biomedical subjects

M Li

Publications and source records attributed to M Li.

At least 253 records · Page 14Linked to original sources
PubMed2001

[A computer-aid study on the craniofacial features of Archang race in Yunnan province of China].

OBJECTIVE: Archang race is one of special minoritis in Yunnan province of China. However, there is not former report about overall craniofacial features in Archang race, therefore a computerized measurement on craniofacial features of Archang race was established in this study. METHODS: On the basis of the principles of random sampling, the craniofacial features of 196 normal adults of Archang race coming from Longchuan County, Dehong Dai Jingpo nationality autonomous prefecture in Yunnan province of China were investigated using the craniofacial video-computerized measurement system which was developed by us. RESULTS: Totally 41 measured items and 17 indexes of craniofacial features were obtained from male and female adults of Archang race. On the basis of 5 indexes, the people were classified according to the head, facial, and nose forms. CONCLUSION: The results of this study are of great importance in terms of that the reference is not only significant for anthropology, ethnology, but also for medicine and industry.

Aged↗
PubMed2001

[Clinical significance of trigeminal neuralgia treated using radiofrequency thermocoagulation (RFT) with different approaches].

OBJECTIVE: The authors presented the short term and long term effects of the trigeminal neuralgia treated by RFT with anterior-lateral facial, lateral facial and trans-subzygomatic approaches. METHODS: 320 primary patients with trigeminal neuralgia were selected for this study. All these patients were followed up with the period of 1 to 6 years. RESULTS: The first-time effective ratios of pain-relieve treated by using the anterior-lateral facial approach, and the lateral facial and the trans-subzygomatic, were 93.3% and 73.3% respectively. Most of the patients (92.5%) achieved excellent or good pain-relieve after treated by one of these three approaches. Compared with the lateral facial and trans-subzygomatic procedures, the anterior-lateral facial approach caused less recurrent rate in long term effects (P < 0.01). The late recurrence was found in 93 patients, but pain-relieve effect still could be obtained by retreating with the former method and without difficulty or hazard. One patient had serious Rollets syndrome. CONCLUSION: It is concluded that the anterior-lateral approach is a method with more effective pain-relieve and less pain recurrence rate, and the trans-subzygomatic method can be used as a substitutive approach in the treatment of the second branch of trigeminal neuralgia.

Adult↗
PubMed2001

[Study on sampling preconcentration method combining electrostacking with isotachophoresis in capillary electrophoresis].

A sampling preconcentration method combining electrostacking with isotachophoresis is presented in this paper. The optimum conditions for electrostacking and isotachophoresis were investigated. With the preconcentration conditions of 70 s electrostacking and 40 s isotachophoresis, two medicines, propranolol and metoprolol, with similar structures were separated by capillary zone electrophoresis. The working voltage for all the steps was 15 kV. Being adjusted to pH 4.0, 30 mmol/L NaAc-HAc, 30 mmol/L beta-alanine-HAc and 1.5 mmol/L NaAc-HAc were employed as the background, viz. leading, terminating and sample buffer solutions respectively. In comparing with the conventional electro-migration injection, the enhancement factors in peak height of the present method were about 250 and 160 for propranolol and metoprolol respectively. Total analysis time was similar to that of the conventional one.

Electrolytes↗
PubMed2001

[Study on the application of quantitative analysis of cell-wall amino acids in actinomycetes classification].

This paper has collected 70 recognized type strains of actinomycete from home and abroad Microbiological culture collection centers. Adopting thin-layer chromatography and thin-layer chromatogram scanner methods to quantitatively analyze the composition of cell-wall amino acids in actinomycete. It has made comparison between quantitative results and qualitative ones. After a thorough discussion, a revision is made on the standard of dividing cell-wall types in actinomycete chemical classification, which has provided some original suggestion in hope of improving the research of actinomycete chemical classification.

Actinobacteria↗
PubMed2001

[Identification of Mortieralla isabellina M6-22 delta 6-fatty acid desaturase by heterologous expression in Saccharomyces cerevisiae].

Using plasmid pTMICL6 containing delta 6-fatty-acid desaturase gene from Mortieralla isabellina M6-22 as a template, 1.38 kb DNA fragment was amplified by PCR. The fragment was subcloned into the yeast-E. coli shuttle vector pYES2.0, then an expression recombinant plamid pYMID6 containing target gene was constructed. The pYMID6 was transformed into Saccharomyces cerevisiae for expression by LiAc method. It was found to exhibit delta 6-fatty acid desaturase activity in the recombinant S. cerevisiae YMID6 in the presence of exogenous fatty acid substrate linoleic acid under introduction of GAL. Expression of the delta 6-fatty acid desaturase gene under appropriate media and temperature conditions led to the production of gamma-linolenic acid reached 8.69% of the total yeast fatty acid by GC-MS detection. It is the first report about expression of M. isabellina D6D gene in S. cerevisiae.

Fatty Acids↗
PubMed2001

[The management of posterior capsular in cataract operations of high myopia].

OBJECTIVE: To study the management of posterior capsular in cataract operation of high myopia in order to avoid posterior capsular opacity(PCO). METHODS: Twenty-two cases(30 eyes) of high myopia with an average axial length of 31.62 mm were analyzed. Cataract phacoemulsification were performed in all cases, among which 12 eyes were operated with continuous curvilinear capsulorhexis (group I) of posteror capsular and 18 eyes were operated with capsulorectomy combined with anterior segment vitrectomy (group II). No artificial lenses were implanted in all cases. RESULTS: The post-operative naked vision were improved in both groups. Group I: The VA > or = 0.1 in all 12 eyes(100%), > or = 0.3 in seven eyes (58.3%) and no complication happened. Group II: The VA > or = 0.1 in 16 eyes(88.9%), > or = 0.3 in nine eyes (50%), and one eye with hemmorhage choroid detachment in the operation and three eyes with retina tear after the operation. CONCLUSION: Continuous curvilinear capsulorhexis of posteror capsular in treating PCO of high myopia with cataract is a safe effective and economic way compared with capsulorectomy combined with anterior segment vitrectomy.

Adult↗
PubMed2001

[Character of alpha-crystallin molecular chaperone activity in selenite cataract].

PURPOSE: To evaluate the character of alpha-crystallin molecular chaperone activity in selenite cataract. METHODS: alpha-Crystallin from lenses of normal young rats and lenses with selenite cataract were separated and purified by gel filtration chromatography. The chaperone activity of alpha-crystallin was assayed by mearsuring heat-induced aggregation and scattering of catalase. RESULTS: alpha-Crystallin in both normal and cataractous lenses specifically prevented catalase against thermal aggregation compared with control proteins. The preventive ability in alpha H-crystallin was less than in alpha L-crystallin. Chaperone activity was diminished in selenite cataract. There was statistically significant difference in chaperone activity between normal and cataractous lenses in both alpha H-crystallin and alpha L-crystallin respectively. CONCLUSION: The reduction of alpha-crystallin chaperone activity in selenite cataract by preventing thermal aggregation of catalase is an important process in cataract formation.

Animals↗
PubMed2001

[Expression and immunocompetence characterization of Plasmodium falciparum lactate dehydrogenase].

OBJECTIVE: To express lactate dehydrogenase (LDH) gene of Plasmodium falciparum FCC1/HN in the E. coli TG1 and analyse its immunocompetence. METHODS: The LDH gene of the P. falciparum was specifically amplified by polymerase chain reaction, and the recovered gene fragment was cloned into pGEX-4T-1 vector for expression of fusion protein with glutathione S-transferase(GST). The recombinant plasmid was transformed into the E. coli TG1. Four mice (Kunming strain) were immunized with purified expressed protein(antigen) and the polyclonal antibodies were collected. The immunocompetence of recombinant protein was analysed by ELISA and Western-blot. RESULTS: The LDH gene of P. falciparum was successfully expressed in the E. coli TG1. The expressed protein exhibited a specific reaction with immune sera obtained from rabbits immunized with P. falciparum. The specific humoral responses were induced in mice and the titer of the specific antibody was 1:16 by two-dimensional diffusion assay. CONCLUSION: The LDH gene of P. falciparum has been successfully expressed in the E. coli TG1 and the expressed protein has high antigencity.

Animals↗
PubMed2001

[Studies on the sex difference in proteins between male and female adult worm of Schistosoma japonicum].

OBJECTIVE: To explore the sex difference in proteins between male and female adult worm of Schistosoma japonicum. METHODS: Two-electrophoresis was used to analyse the difference of protein between the male and female adult worm of S. japonicum (Chinese strain). RESULTS: Two-dimensional electrophoresis analysis revealed that at the site of 43 kDa and an isoelectric point (pI) of 5.60-5.90 the male worm exhibited a band carrying a number of spots and dots, being longer and wider than that exhibited by the female worm. The female worm exhibited 7 specific dots. CONCLUSION: The sex differences in proteins between male and female adult worms of S. japonicum are significant.

Animals↗
PubMed2001

[Effect of decreased bite force on the temporal and spatial expression of type I collagen mRNA in rat molar periodontal ligament].

OBJECTIVE: The aim of this study was to observe the effect of decreased bite force on type I collagen mRNA in periodontal ligament (PDL) and probe into the molecular mechanism of the change in type I collagen mRNA. METHODS: Animal models were established by extracting left maxillary molars of rats. In situ hybridization was applied. RESULTS: The results showed that under decreased bite force, the expression level of type I collagen mRNA decreased at the sixth hour (49.7 +/- 11.1) (P < 0.05), reached the nadir on the second day (23.7 +/- 8.6), began to get over on the third day (43.1 +/- 10.3), and reached a relatively high level at the second week(56.3 +/- 9.8), but it was still lower than that of the normal bite force group (91.4 +/- 16.0)(P < 0.05); the expression of type I collagen mRNA near the cementum was higher than that near the alveolar bone. CONCLUSION: These results indicate that the expression level of type I collagen mRNA is closely related to bite force.

Animals↗
PubMed2001

[Effect of increased and decreased bite force on morphology of periodontal tissues].

OBJECTIVE: The aim of this study was to observe the effect of bite force on morphology of periodontal tissues. METHODS: Animal models were induced by extracting the left maxillary molars; the left mandibular molars served as decreased bite force models; the right mandibular molars served as increased bite force models. The dynamic changes of widths of periodontal ligament and cementum were measured. RESULTS: In decreased bite force group, there were significant morphologic changes of periodontal tissues after 1 week. In increased bite force group, there was no significant change. Ligament widths were significantly different after 2, 3 weeks respectively in those two groups, compared with that in control group (P < 0.05). There were significant differences between proximal alveolar wall and distal alveolar wall in width (P < 0.05). CONCLUSION: The histological morphology is closely related to the mechanical condition. Physiological bite force is necessary for periodontal ligament to maintain its physiological structure.

Animals↗
PubMed2001

[Clinical study of the sentinel lymph node of patients with laryngeal and hypopharyngeal carcinomas].

OBJECTIVE: To investigate the methods of detecting the sentinel lymph node of laryngeal and hypopharyngeal carcinomas and its predictive value in the cervical metastasis of the carcinoma. METHODS: In 29 patients who suffered from laryngeal or hypopharyngeal carcinoma with NO neck, the patent blue was injected into the surrounding tissue of the tumor during the operation to identify the sentinel lymph nodes. The sentinel lymph nodes were dyed blue. The frozen histopathology was done during the operation, the lymph nodes at the ipsilateral side of the neck were dissected completely, and the routine histopathology was done as the gold standard to study the predictive value of the sentinel lymph node in the metastasis of the cervical node. RESULTS: Of 29 patients, 28 patients' sentinel lymph nodes were detected successfully during operation. There was an average of 2.5 lymph nodes per side per patient. Most of the sentinel lymph nodes were in the level II and level III regions of the ipsilateral side of the neck, and there were bilateral sentinel nodes in patients suffered from superglottic carcinoma. Three patients' sentinel lymph nodes were found to be positive in the frozen inspection, and the routine histopathology confirmed the result. The micrometastasis rate was 10.7% (3/28). There were no metastatic lymph nodes found in patients who were negative for the sentinel lymph nodes during the operative frozen histopathology. The predicted value of the sentinel lymph nodes to the cervical lymph node metastasis was 100 per cent. CONCLUSION: There is a very important predicted value of sentinel lymph nodes in the cervical metastasis of patients suffered from laryngeal and hypopharyngeal carcinomas. It could reduce the neck dissection in patients with laryngeal and hypopharyngeal carcinomas.

Adult↗
PubMed2001

Potentiation of docetaxel antitumor activity by batimastat against mouse forestomach carcinoma.

OBJECTIVE: To improve the treatment of tumors, we studied the combined effects of docetaxel and batimastat (BB-94) on mouse forestomach carcinoma (MFC), and compared them with doxorubicin. METHODS AND RESULTS: In vitro, growth curve analysis, MTT assay and clonogenic assay used to determine the cytotoxic effect of docetaxel or/and BB-94 on MFC cell showed that docetaxel but not BB-94 had a significant cytotoxicity, and the effect of docetaxel wasn't enhanced by BB-94. In early stage MFC tumor model, obvious antitumor effect of docetaxel or doxorubicin given i.v. at maximum tolerated dose (MTD, docetaxel: 20 mg/kg; doxorubicin: 6 mg/kg) every 4 days for 3 injections (q4d x 3), even that of BB-94 (30 mg/kg i. p. qd x 20) was observed. Tumor growth inhibition was greater for docetaxel-batimastat (96.0%) than for doxorubicin-batimastat (88.0%), docetaxel (89.0%), doxorubicin (68.0%) and BB-94 (33.0%), and the effect of docetaxel could be potentiated by BB-94. Docetaxel also showed activity against advanced stage MFC tumor in dose-dependent manner, and was more effective at MTD than doxorubicin with 4/5 regressions, 46.5 days tumor growth delay and 2.8log(10) tumor cell kill. CONCLUSION: Our results suggest that in the MFC model with dose and schedule used, docetaxel is an effective cytotoxic new drug against MFC tumor and BB-94 enchances the antitumor activity of docetaxel.

Animals↗
PubMed2001

[Polymorphism of parathyroid hormone gene and its association with bone mineral density of Han nationality women in Beijing area].

OBJECTIVE: To investigate the distribution of frequency of parathyroid hormone(PTH) gene polymorphisms in healthy adults of Han nationality in Beijing area and relationship between PTH genotypes and bone mineral density(BMD) in young and postmenopausal women. METHODS: Polymorphism of PTH gene were detected by polymerase chain reaction restriction fragment length polymorphism(PCR-RFLP) of restriction enzyme Bst B1 in 270 subjects. If the site of enzyme Bst B1 existed, the PTH genotype was "B". On the contrary, if base mutation occurred, the genotype was "b". Some of the PTH genotypes were confirmed by DNA sequences analysis. Bone mineral density(BMD) was measured by dual-energy X-ray absorptiometry. RESULTS: Genotype frequencies of BB, Bb, bb were 73.7%, 25.9%, and 0.4% respectively in adults of Beijing areas. The frequencies of RFLP alleles B, b were 86.7% and 13.3%. Beijing postmenopausal women frequencies of BB, Bb, bb were 67.1%, 32.2% and 0.7%. B, b alleles frequencies were 83.2% and 16.8%. We statistically compared bone mineral density at the lumbar 2-4, neck, wards triangle and trochanter major, there was no significant difference between BB and Bb genotype of young women and postmenopausal women groups. Otherwise, no obvious relationship was found between the BMD and PTH genotype in Beijing women. CONCLUSIONS: PTH gene polymorphisms were not associated with BMD in Beijing women.

Adult↗
PubMed2001

[Upconversion luminescent dynamics of HoP5O14 noncrystallite excited by DCM dye laser].

The dynamics processes of 370-580 nm upconversion luminescence of HoP5O14 noncrystalline excited by DCM dye laser is reported in this paper. It is found that both mechanisms of energy transfer upconversion among ions and step-wise multiphoton absorption of single ion are involved in the upconversion luminescence, the upconversion dynamics would change greatly when the frequency of pumping laser has a little variation.

Crystallization↗
PubMed2001

[Study on the detaining effect of hypocrelin a in the cancer cell using microspectrum].

Microspectra of mouse lymph cancer cells which one is cultured with HA and the other is cultured without HA have obtained in the range of 20,000-12,000 cm-1. The result shows tha two microspectra are quite different. This point out the cancer cell has changed because of HA. In the microspectrum of cancer cell cultured with HA, we have got the fluorescent peak of HA. This prompts HA has detained in the cancer cell. A new method which studies cells after being affected by drugs using microspectrum has also being developed.

Animals↗
PubMed2001

[The upconversion "characteristic saturation phenomenon" of ErYb:ZBLAN glass excited by 966 nm diode laser].

This paper researches the upconversion luminescence of Er:ZBLAN and ErYb:ZBLAN glasses excited by 966 nm diode laser. It is found that there is a new kind of "characteristic saturation phenomenon". It is that the log-log plot's slope of upconversion luminescence intensity upon laser power of ErYb:ZBLAN glass is decreased clearly than that of Er:ZBLAN, and both of their log-log plots are rather good straight line. This upconversion mechanism is a new kind of "diffusion-transfer" mechanism, that is energy diffusion among Yb3+ ions sequential followed by energy transfer between Er(3+)-Yb3+ ions. The "characteristic saturation phenomenon" is just resulted from energy diffusion.

English Abstract↗